Method for producing an assembly of solar cells overlapping via an interconnection structure

Abstract

Disclosed is an assembly of solar cells provided with a connection structure (40) arranged opposite and between a peripheral zone of a first solar cell and a second peripheral zone of a second solar cell, the connection structure providing increased mechanical flexibility and comprising: - an oblong conductive portion (41), - a set of conductive blocks (42, 43) distributed over the oblong conductive portion, alternately over a first region (41A) of the oblong conductive portion (41) and over a second region (41B) of the oblong conductive portion (41) opposite the first region (41A).

Description

TECHNICAL FIELD

[0001] This application relates to the field of photovoltaic (PV) cells, also called solar cells, and more particularly to their assembly and interconnection.

[0002] It relates to an assembly of solar cells with a particular interconnection structure, to the production of such an assembly and to a photovoltaic module comprising such an assembly. STATE OF THE PRIOR ART

[0003] A conventional solar cell interconnection technique is based on the use of an electrically conductive metal ribbon that provides the electrical connection between one cell and the next.

[0004] Such a type of interconnection is illustrated in the Figure 1Ain the particular case of cells 11, 12, 13 with rear face contact (RCC), the metal strip 4 here connecting an electrode 3a arranged on the rear face 2B of a cell 11, 12 and an electrode 3b arranged on the rear face of another cell 12, 13.

[0005] According to a variant, illustrated on the Figure 1B , the metal strip 4 here connects an electrode 3a arranged on the front face 2A of a cell 11, and an electrode 3b arranged on the rear face 2B of another cell 12.

[0006] In this case, the cells are usually arranged next to each other and this results in a surface 5 which is lost between the cells, which increases the size of the assembly and is therefore called a "dead zone".

[0007] Another assembly technique called "Shingle" (in French tiling), makes it possible to limit the size and consists of superimposing the edges of cells 1 1 , 1 2 , on a small surface. The interconnection between a conductive zone 7 on the front face 2A of a cell 1 1 and a conductive zone 8 on the rear face 2B of another cell 1 2 is then carried out by means of a conductive material 9, of the solder material type added at the level of an overlap zone between the cells or conductive glue of the ECA type (for Electro Conductive Adhesive) based on Acrylate or Epoxy. This interconnection structure has the advantage of not creating a dead zone between cells 1 1 , 1 2 . However, it results in a rigid mechanical structure which can be fragile when it undergoes significant thermomechanical stresses.

[0008] The document "Materials Challenge for shingled cells interconnection" by Beaucarne et al., 6th workshop on metallization and interconnection for crystalline silicon solar cells, 2016, proposes a Shingle-type assembly using an ECA glue (ECA for "Electrically Conductive Adhesive") with a silicone base (more mechanically flexible than acrylate or epoxy) in order to make the final assembly more flexible. Such a structure, however, allows little deformation in the cell plane. WO 2017 / 190398 A1 relates to a connection structure in an assembly of overlapping solar cells.

[0009] The problem arises of finding a new interconnection technique that is improved in view of the disadvantages stated above. STATEMENT OF THE INVENTION

[0010] According to the invention, a method is provided for producing a solar cell assembly, according to claim 1. The solar cell assembly described below is not part of the invention but represents an element which is useful for understanding the invention. The production of a solar cell assembly comprising: a first solar cell connected to a second solar cell, the second solar cell being arranged so that a peripheral zone of a rear face of the first cell called "first peripheral zone" overlaps a peripheral zone of the front face of the second cell called "second peripheral zone", the assembly further comprising: a connection structure arranged opposite and between said first peripheral zone and said second peripheral zone, said connection structure being formed: of at least one oblong conductive portion, of a succession of conductive blocks arranged against and in contact with said oblong conductive portion and in an overlap zone between said first peripheral zone and said peripheral zone,said conductive blocks being alternately distributed over a first region (typically a first face) of oblong conductive portion and over a second region (typically a second face opposite the first face) of said oblong conductive portion opposite said first region, one or more first blocks among said first conductive blocks being in contact with said first peripheral zone, one or more second conductive blocks being in contact with said second peripheral zone.

[0011] Such a structure allows for mechanical decoupling between the cells and gives the assembly increased flexibility, making it more resistant to thermomechanical stresses.

[0012] Preferably, all of said one or more second conductive blocks are offset relative to all of said one or more first conductive blocks, which allows better deformation in a plane parallel to the cells and contributes to making the assembly more flexible and therefore resistant to certain thermomechanical stresses.

[0013] Advantageously, one or more or each of said one or more first conductive blocks may be opposite an empty space and / or an area of ​​insulating material disposed between said second region of said oblong conductive portion and said second peripheral area.

[0014] Advantageously, one or more second conductive blocks or each of the second conductive blocks may be arranged opposite an empty space and / or an area of ​​insulating material disposed between said first region of said oblong conductive portion and said first peripheral area.

[0015] Depending on the implementation possibility, this insulating material can be a polymer material. This type of material has the advantage of having a low Young's modulus, which promotes the flexibility of the assembly.

[0016] According to a particular embodiment, at least one of said one or more first conductive blocks may be surrounded by an insulating passivation zone arranged between said first oblong conductive portion region and said first peripheral zone of the first cell.

[0017] According to a particular embodiment, at least one of said one or more second conductive blocks may be surrounded by an insulating passivation zone arranged between said second region of said oblong conductive portion and said first peripheral zone of the first cell.

[0018] The oblong conductive portion may advantageously be in the form of at least one conductive wire, or of several separate juxtaposed conductive wires or even of a conductive strip, in particular a flat strip.

[0019] A particular embodiment provides said conductive blocks in the form of conductive glue dots, in particular a glue made of polymer material loaded with conductive particles, such as an ECA type glue. In this case, the flexibility of the assembly can be promoted.

[0020] In this case, a connection structure with lower electrical contact resistance can be obtained.

[0021] According to a particular embodiment, said conductive blocks have a substantially rectangular or substantially parallelepiped shape with rounded corners. Such a shape of the conductive blocks can also make it possible to obtain increased flexibility of the structure.

[0022] The invention relates to a method for producing a solar module having an assembly as defined above.

[0023] The invention relates more specifically to a method for producing an assembly of solar cells, said assembly comprising a first cell connected to a second cell, said second cell being arranged so that a peripheral zone of a rear face of the first cell called "first peripheral zone", overlaps a peripheral zone of the front face of the second cell called "second peripheral zone", the method comprising steps of: producing a connection structure formed: of at least one oblong conductive portion, and of a succession of conductive blocks, said conductive blocks projecting from the oblong portion and being conductive glue points, said conductive blocks being arranged alternately on a first region of oblong conductive portion and on a second region of said oblong conductive portion opposite said first region, then, assembling the connection structure with the first cell and the second cell, the connection structure being arranged opposite and between said first peripheral zone and said second peripheral zone, in an overlapping zone between said first peripheral zone and said second peripheral zone, one or more first blocks among said first conductive blocks being in contact with said first peripheral zone,one or more second conductive blocks being in contact with said second peripheral zone, all of said one or more second conductive blocks being offset relative to all of said one or more first conductive blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be better understood upon reading the description of exemplary embodiments given, for purely indicative and non-limiting purposes, with reference to the appended drawings in which: THE Figures 1A, 1B are used to illustrate a conventional technique for assembling and interconnecting solar cells using conductive tape; The figure 2 serves to illustrate another technique for assembling and interconnecting solar cells according to the prior art, in which the solar cells overlap and are connected by means of a solder material or an ECA material; The figures 3, 4, 5 and 6are used to illustrate a solar cell interconnection and assembly structure according to one embodiment, the assembly being carried out without dead zones and having increased flexibility; The figure 7 serves to illustrate the behavior of the interconnection structure when it undergoes thermal and / or mechanical stress; The figure 8 are used to illustrate performance differences in terms of average energy density accumulated in a connection structure compared to a conventional connection structure; Figures 9A, 9B are used to illustrate different densities of contact conductor blocks in a solar cell interconnection structure as implemented according to the invention; The figure 10 serves to illustrate differences in electrical performance between an interconnect structure and an interconnect structure as implemented in accordance with the present invention; The figures 11, 12 , 13 and 14are used to illustrate an alternative solar cell interconnection structure with multiple separate parallel conductive wires; The figures 15,16 serve to illustrate another alternative solar cell interconnection structure; The Figures 17A, 17B, 17C and 17D serve to illustrate steps of an exemplary method of assembling and interconnecting solar cells as implemented according to an embodiment of the present invention; The Figures 18A, 18B, 18C and 18D serve to illustrate another example of a method of assembling and interconnecting solar cells as implemented according to an embodiment of the present invention;

[0025] Identical, similar or equivalent parts of different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0026] The different parts represented in the figures are not necessarily on a uniform scale, to make the figures more readable.

[0027] Furthermore, in the following description, terms which depend on the orientation of the structure such as "front", "upper", "rear", "lower", "lateral", "central", "peripheral" apply considering that the structure is oriented as illustrated in the figures. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0028] We now refer to the figure 3 giving (by means of an exploded view) an assembly of solar cells 10 1 , 10 2 as implemented according to an embodiment of the present invention.

[0029] The solar cells 10 1 , 10 2 are formed from a semiconductor substrate, which may be poly- or mono-crystalline and in particular based on polycrystalline or monocrystalline silicon. Each of the cells 10 1 , 10 2 is provided with at least one face 2A called the “front face”, which receives light and is intended to be exposed to solar radiation, and a face 2B called the “rear face”, opposite the front face 2A. The rear face 2B may optionally also be intended to be exposed to solar radiation. In this particular case, the cell is said to be “bifacial”.

[0030] At least one first solar cell 10 1 of this assembly is provided with contacts distributed on the rear face 2B, including one or more contacts (not shown) with respectively one or more N-type doped zones (in other words having a doping producing an excess of electrons) and one or more contacts (not shown in this figure) with respectively one or more P-type doped zones (in other words according to a doping consisting of producing a deficit of electrons), the N-type zone(s) associated with the P-type zone(s) forming at least one junction.

[0031] The assembly is such that a peripheral zone 23B located on the rear face 2B of the first cell 10 1 is arranged opposite a peripheral zone 22A of the front face 2A of a second cell 10 2 .

[0032] The solar cells 10 1 , 10 2 are thus assembled here according to an assembly of the type called “shingle”, in other words so as to partially overlap, which in particular makes it possible to achieve a compact assembly. The overlap can be provided over a distance typically of at least 0.2 mm and which can be, for example, between 0.5 mm and several millimeters.

[0033] In addition to the assembly, the connection of the cells 10 1 , 10 2 to each other is carried out here using a particular connection structure 40 which is arranged between the cells 10 1 , 10 2 , and is preferably confined at a region where they overlap.

[0034] This connection structure 40 is formed of an oblong conductive portion 41 which, in the particular embodiment illustrated in the figure 3, is in the form of a conductive strip. On and in contact with the external surface of this oblong conductive portion 41, projecting conductive blocks 42, 43 are provided to be placed in contact respectively with the solar cells 10 1 , 10 2 and to ensure an electrical connection from one cell to the other.

[0035] The conductive blocks 42, 43 are distributed alternately over a first region 41A of said conductive portion 41 placed opposite the peripheral zone 23B of the first cell 10 1 and over a second region 41B, opposite the first region, of said conductive portion 41, the second region being arranged opposite the peripheral zone 22A of the second cell 10 2. In the case where the oblong conductive portion 41 is in the form of a conductive strip of planar shape, the first region 41A and the second region 41B are respectively a first face 41A and a second face 41B opposite the first face 41A.

[0036] The connection structure 40 thus comprises one or more first conductive blocks 42 on the first face 41A and one or more second conductive blocks 43 on the face 41B opposite the first face 41A.

[0037] Confining the connection structure 40 and the conductive blocks 42, 43 to the overlap region of the cells 10 1 , 10 2 makes it possible not to obstruct parts, including the rear face 2B, which one might want to expose to solar radiation.

[0038] In order to provide flexibility to the assembly, the blocks 42, 43 are here distributed along an axis AA', alternately on the first face 41A and on the second face 41B, with, preferably, an offset provided from one conductive block 42 to the other 43 along this axis AA'. The entire block(s) 42 formed on the first face 41A is thus offset from the entire block(s) 43 located on the second face 41B.

[0039] Thus, in the succession of conductive blocks 42, 43, along the axis AA' each conductive block 43 is offset from the following block 42.

[0040] Thus, as shown by the figures 4, 5, 6 (giving sectional views of the assembly respectively along an axis AA', an axis BB', an axis CC' given on the figure 1), the conductive blocks 42 and the conductive blocks 43 are misaligned so that a conductive block 42 located on the first face 41A of the conductive strip 41 and in contact with the first cell 10 1 is not arranged opposite or entirely opposite a second conductive block 43 of the second face 41B but rather at least one space 36 provided between the second face 41B and the second cell 10 2 . Similarly, a conductive block 43 located on the second face 41B of the conductive strip 41 and in contact with the second cell 10 2 is not arranged opposite or entirely opposite a first conductive block 42 located on the first face 41A but at least one space 38 provided between the second face 41B and the first cell 10 1 .

[0041] This arrangement implies that the electrical connection between the two cells 10 1 and 10 2 is not established along a vertical conduction path (axis parallel to the vector z of the orthogonal reference frame [O; x; y; z]), but along an 'S' path. Such an arrangement makes it possible to promote mechanical decoupling between the cells 10 1 , 10 2 and allows deformation of the cells 10 1 , 10 2 following thermomechanical stress or following manipulation of the assembly of cells 10 1 , 10 2 .

[0042] The oblong conductive portion 41, when in the form of a strip, may be provided with a width W (smallest dimension measured in a plane parallel to the cells and to the plane [O; x; y]) of, for example, between 0.1 and several millimeters, and advantageously between 0.2 mm and 1 mm. Typically, the width W of the strip corresponds to the overlap width between the cells 10 1 , 10 2 , for example of the order of 1 mm. The strip may also be provided with a thickness e (dimension measured parallel to the z axis) of, for example, between 10 µm and 500 µm, for example of the order of 50 µm. The strip may optionally extend over the entire length of a cell.

[0043] The conductive blocks 42, 43 may be provided with a thickness of, for example, between 5 µm and 200 µm, for example of the order of 50 µm. This thickness is adapted in particular according to the number of blocks, their surface area and their distribution pitch on the oblong conductive portion 41.

[0044] With regard to the composition of the structure, the oblong conductive portion 41 may be formed from one or more metallic material(s) such as, for example, copper or silver or tinned copper. A particular embodiment provides a conductive portion 41 formed from a core of conductive material, in particular a metallic material such as copper or silver, coated with areas of insulating material forming a discontinuous insulating sheath around the conductive blocks. The insulating material may be a polymer, for example a polyimide such as Kapton ™< .

[0045] The conductive blocks 42, 43 are typically made of a material different from that of the oblong conductive portion 41 and may in particular be attached to this oblong conductive portion 41 typically in the form of conductive glue dots or areas of solder material.

[0046] For example, when the conductive blocks 42, 43 are brazing areas, they may be formed from a tin-silver-copper (SnAgCu, also known as SAC) metal alloy which is a lead-free alloy. In particular, an alloy of the "SAC305" type composed of more than 95% tin, about 3.0% silver and about 0.5% copper may be used.

[0047] When the conductive blocks 42, 43 are conductive glue points, an ECA (Electrically Conductive Adhesive) glue can be used. Such an adhesive is formed from a polymer matrix, typically of the epoxy, acrylate or silicone type, loaded with conductive particles. For example, a silver epoxy glue of the EPO-TEK ®< H20E, Loctite ®< 8282 or Loctite ®< 8311 type can be used in particular.

[0048] Thus, with such a connection structure 40, the conductive blocks 42, 43 ensure both mechanical and electrical contact on the cells 10 1 , 10 2 , while the oblong portion 41 makes it possible to ensure mechanical decoupling between the cells and for the assembly to resist thermal and / or mechanical stresses.

[0049] As shown on the figure 7, such decoupling can allow the connection structure 40 (shown in top view) to deform when it undergoes thermal and / or mechanical stress, without however degrading the cells, the latter being typically made of a material having significant rigidity such as silicon.

[0050] In the example of realization illustrated on the figures 3, 4, 5, 6 empty spaces 38, 36 are provided between the connection structure and the cells 10 1 , 10 2 . Alternatively and as suggested previously, these spaces may be at least partially filled by at least one insulating passivation material, for example a material with a low Young's modulus, in particular a polymer such as for example Kapton ™< .

[0051] Numerical stress simulations using the Ansys ® tool were performed to compare a connection structure as described above with a conventional connection structure using a simple conductive strip between two overlapping cells. Results of such a simulation are given by the graph of the figure 8 .

[0052] For the conventional structure, the interconnection consists of a continuous bead of ECA type glue, 50 µm thick and 156 mm long, corresponding to an M2 format of solar cells. The glue material is considered to have a Young's modulus of 1 GPa.

[0053] At the same time, a connection structure as implemented according to the invention is considered, with at least three conductive blocks (two on one face, one on another face) on a conductive copper strip of length 156 mm with a Young's modulus for copper of 124 GPa.

[0054] The number of conductive blocks is varied from 3 to 50 to assess the evolution of the deformation capacities of the structure according to the invention.

[0055] For each of the established simulation models, an arbitrary deformation of 1 µm is applied.

[0056] Since the simulated geometries and materials are not identical between the two structures, mechanical stress levels are not compared. The output data chosen for comparison here is an average elastic energy density accumulated in the complete interconnect following a deformation of 1 µm. This data can be considered the inverse of mechanical flexibility. The results are represented by the C 40 curve normalized to the conventional interconnect (C conv ).

[0057] On the one hand, it is observed that the average density of elastic energy accumulated in the connection structure according to the invention always has a lower value than the reference structure. As regards the influence of the number of conductive protrusions, even considering 50 protrusions (which, in the present case, is equivalent to an electrical connection point every 1.5 mm), the level of accumulated energy is 5 times lower than that present in the case of a conventional connection structure.

[0058] THE Figures 9A and 9B show cells 10 1 , 10 2 before assembly, with different densities of conductive blocks 42, 43 at areas 23B, 22A

[0059] There Figure 9Aallows to illustrate a first case of a small number n of conductive blocks, for example equal to 3, along each cell. In this case, in order to distribute the current in all the conductive fingers 47 on the cell surface, it is possible to provide a greater thickness of the conductive zones 46 on which they are in contact and which is produced for example by screen printing with silver paste.

[0060] In a second case ( Figure 9B ) of a large number of conductive blocks along the cells to be connected (n=50), the conductive zone 46 can be provided with a thickness of a conventional Shingle assembly.

[0061] The geometric optimum of the connection structure and in particular the number, size and density of the conductive blocks 42, 43 depends on a compromise between necessary mechanical flexibility while guaranteeing sufficient electrical performance of the interconnection.

[0062] There figure 10illustrates the result of a comparison between the series resistance of a first connection structure according to the invention (curve C 1 ) and that of a second connection structure according to the invention (curve C 2 ).

[0063] The first connection structure according to the invention (curve C 1 ) is here formed of a copper strip with dimensions thickness*length*width of 0.05*156*1mm and conductive blocks projecting from the strip and formed of a brazing material of type SAC305. The brazing zones have dimensions of 0.05*1*1mm (thickness*length*width).

[0064] The series resistance of a second interconnection as implemented according to the invention with ECA type glue dots is also illustrated (curve C 2 ).

[0065] The comparison is carried out using an analytical calculation (R=(Rho*L) / S), with R the electrical resistance of the material, Rho the resistivity of the material, L the length and S its section, considering resistivities for Copper of 17e-9 ohm.m, for SAC305 solder: 1.3e-6 ohm.m, for ECA glue of 4 e< -2 ohm.m.

[0066] The results presented in the form of curves C 1 , C 2 as a function of the number n of glue points or soldering zones along the overlap zone between cells.

[0067] The structure according to the invention makes it possible to use a solder-type material for the connections on the cells. It is observed that the interconnection proposed in this invention always has a theoretical electrical resistance lower than that of a conventional structure.

[0068] Another example of an interconnection structure between cells 10 1 , 10 2 is given on the figures 11 to 14giving respectively an exploded view, a sectional view AA', a cross-sectional view BB', and another sectional view CC' according to another cross-sectional plane). The oblong portion of the connection structure this time takes the form of conductive wires 81, 91 juxtaposed and preferably arranged one parallel to the other.

[0069] The conductive blocks 42, 43 (not shown on the figure 11for the sake of simplification) distributed respectively on the conductive wires 81, 91 and under the conductive wires 81, 91 may have an arrangement similar to that described above. The structure here comprises passivation zones 54, 55 distributed respectively on the conductive wires 81, 91, and under the conductive wires 81, 91. Thus, one or more passivation zones 54 are arranged between the first cell 10 1 and an upper face of the conductive wires 81, 91, while one or more other passivation zones 55 are arranged between the second cell 10 2 and a lower face of the conductive wires 81, 91 opposite the upper face. Each passivation zone 54 (resp. 55) may be provided between two conductive blocks 42 (resp. 43).

[0070] The passivation zones 54, 55 may be in the form of a film or a layer of insulating material, for example a polymer material such as Kapton ™<, and transparent in the case where the film is wider than the cell overlap zone and which is attached to the conductive wires 81, 91.

[0071] As can be seen on the figures 13 and 14 , the thickness of the passivation zones may be less than that of the conductive blocks 42, 43. An empty space 56 (resp. 58) may thus be provided between a passivation zone 55 (resp. 54) and the cell 10 2 (resp. 10 2 ) opposite which this passivation zone is located.

[0072] An alternative embodiment with this time a single conductive wire 81 to make the connection between conductive blocks 42 connected to the cell 101 and conductive blocks 42 connected to the cell 101 is given in the cross-sectional views of the figures 15 and 16 .

[0073] The conductive wire 81 has a parallelepiped shape in the illustrated example. A cylindrical wire can also be used.

[0074] With regard to its manufacture, a connection structure 40 as described above can be produced in several ways.

[0075] A first possibility consists of functionalizing the oblong portion 41 and then carrying out the assembly with the cells. Thus, the conductive blocks 42, 43 are formed on the oblong portion 41, for example on an upper face and on a lower face of a conductive strip, then the interconnection structure is arranged so that it is interposed in the overlapping zone between the cells 10 1 , 10 2 . The assembly is then carried out.

[0076] For example, one can start with a conductive strip on which one or more conductive blocks are made, for example in the form of conductive glue dots on a first face. The conductive blocks can be made, for example, by screen printing using a masking, possibly temporary, arranged on the first face and comprising one or more openings revealing the first face of the conductive strip.

[0077] Then, one or more conductive blocks are formed on a second face, for example conductive glue dots on a second face opposite the first face. Similarly, conductive blocks can be produced on the second face, for example by screen printing, using for example the same masking or another masking, possibly temporary, arranged on the second face and comprising one or more openings revealing the second face of the conductive strip.

[0078] An illustrated variation on the Figures 17A-17D , plans to produce passivation zones 55, for example in polymer on one face or on one side of the oblong portion ( Figure 17A ), here formed of juxtaposed conductive wires 81, 91, and other passivation zones 54 on the opposite face or on the opposite side. Then, the structure thus obtained is assembled with a cell 10 2 on which conductive blocks 43 in the form of glue dots or soldering zones are arranged ( Figure 17C ). Then, other conductive blocks 42 can be added in the form of glue dots or solder zones on the other cell 10 1 which is then assembled with the previously obtained structure ( Figure 17D ).

[0079] As a variant of this step, the other conductive blocks can be added in the form of glue dots or solder areas on the conductive wires 81, 91 and the assembly is then carried out with the other cell.

[0080] According to another variant illustrated on the Figures 18A-18D , it is first possible to provide for producing one or more conductive blocks 43, for example glue or solder points on a peripheral zone of a solar cell 10 2 ( Figure 18A ). Then, the oblong conductive portion 41 is placed on these conductive blocks 43 ( Figure 18B ).

[0081] Afterwards ( Figure 18C ), we form in another set of conductive blocks 42 on the oblong conductive portion for example points of glue or solder. Then ( Figure 18D ) we place the other cell 10 1 on this other set of blocks 42.

[0082] Such a variant is particularly suitable when the blocks are in the form of solder drops (solder paste).

[0083] According to another variant, one or more conductive blocks can also be made on each cell and then each cell fitted with the conductive blocks can be attached to one of the faces of the conductive strip.

[0084] A particular embodiment provides for distributing the material of the conductive blocks simultaneously at several points on the conductive strip, for example by means of a plurality of dispensing needles delivering drops of glue, in particular an ECA glue.

Claims

1. A method for carrying out an assembly of solar cells, said assembly comprising a first cell (101) connected to a second cell (102), said second cell being arranged so that a peripheral zone (23B) of a rear face (2B) of the first cell called "first peripheral zone" overlaps with a peripheral zone (22A) of the front face (2A) of the second cell called "second peripheral zone", the method comprising steps of: - creating a connection structure (40) formed: by at least one oblong conductive portion (41), and by a succession of conductive blocks (42, 43), said conductive blocks (42, 43) protruding on the oblong portion and being spots of conductive glue, said conductive blocks being arranged alternatingly on a first region (41A) of an oblong conductive portion (41, 81, 91) and on a second region (41B) of said oblong conductive portion (41) opposite to said first region (41A), then - assembling the connection structure with the first cell and the second cell, the connection structure being arranged facing and between said first peripheral zone (23B) and said second peripheral zone (22A), in a zone of overlap between said first peripheral zone and said peripheral zone, one or more first blocks (42) out of said first conductive blocks being in contact with said first peripheral zone (23B), one or more second conductive blocks (43) being in contact with said second peripheral zone (22A), the assembly of said one or more second conductive blocks (43) being offset with respect to the assembly of said one or more first conductive blocks (42).

2. The method according to claim 1, wherein each of said one or more first conductive blocks (42) is arranged facing an empty space (36) and / or a zone of insulating material disposed between said second region (41B) of said oblong conductive portion (41) and said second peripheral zone (22A), and / or wherein each of said one or more second conductive blocks (43) is arranged facing an empty space (38) and / or a zone of insulating material (54) disposed between said first region (41A) of said oblong conductive portion (41) and said first peripheral zone (23B) of the first cell (101).

3. The method according to claim 2, wherein said insulating material is a polymer material.

4. The method according to one of claims 1 to 3, at least one of said one or more first conductive blocks (42) being surrounded by a passivation insulating zone (55) arranged between said first region (41A) of an oblong conductive portion (41) and said first peripheral zone (23B).

5. The method according to one of claims 1 to 4, at least one of said one or more second conductive blocks (43) being surrounded by a passivation insulating zone (54) arranged between said second region (41B) of said oblong conductive portion (41) and said second peripheral zone (22A).

6. The method according to one of claims 1 to 5, wherein said oblong conductive portion (41, 81, 91) is formed by at least one conductive wire (81), or several distinct juxtaposed conductive wires (81, 91) or a conductive strip (41).

7. The method according to one of claims 1 to 6, wherein said conductive blocks (42, 43) are provided with rounded corners.

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